<?php
/**
 * Skyline :: Patterns & component framework
 * Copyright 2010-2011 Ian Unruh (Xerof3ar)
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
namespace Skyline\Comparator;
use Skyline\Transformer\TransformerInterface;

/**
 * Comparator that transforms the values being compared before they
 * are given to another comparator
 * 
 * @author Ian Unruh (Xerof3ar) <ianunruh@gmail.com>
 * @since Class avaliable since release 1.0
 */
class TransformingComparator extends DecoratedComparator
{
	/**
	 * @var TransformerInterface
	 */
	protected $transformer;
	
	/**
	 * Class constructor
	 * 
	 * @param TransformerInterface $transformer
	 * @param ComparatorInterface $comparator
	 * @return void
	 */
	public function __construct(TransformerInterface $transformer, ComparatorInterface $comparator)
	{
		parent::__construct($comparator);
		$this->transformer = $transformer;
	}
	
	/**
	 * Compares a left value to a right value and returns an integer comparison
	 * 
	 * @param mixed $left
	 * @param mixed $right
	 * @return int (-1 = less than, 0 = equal, 1 = greater than)
	 */
	public function compare($left, $right)
	{
		$left = $this->transformer->transform($left);
		$right = $this->transformer->transform($right);
		
		return $this->comparator->compare($left, $right);
	}
	
	/**
	 * Returns the transformer used to transform values before they are compared
	 * @return TransformerInterface
	 */
	public function getTransformer()
	{
		return $this->transformer;
	}
}